Roll clamp for lift truck



Nov. 14, 1961 R. F. OSTER ROLL CLAMP FOR LIFT TRUCK 5 Sheets-Sheet 1Filed Jan. 27, 1958 INVENTOR. ROJEF? 0572 Nov. 14, 1961 R. F. OSTER ROLLCLAMP FOR LIFT TRUCK 5 Sheets-Sheet 2 Filed Jan. 27, 19 58 lr iTizINVENTOR. 205:??- z. Q5721? Nov. 14, 1961 R. F. OSTER 3,008,596

ROLL CLAMP FOR LIFT TRUCK Filed Jan. 27, 1958 5 Sheets-Sheet 3 Nov. 14,1961 Filed Jan. 27, 1958 R. F. OSTER 3,008,596

ROLL CLAMP FOR LIFT TRUCK 5 Sheets-Sheet 4 Dj 4 A v o 60 2-2 W 9 26 IInn 1 I M /4 A;

INVENTOR. 2066,??- E 0:75

zQ/Cbff 4/4774; 50664 704;

Nov. 14, 1961 R. F. OSTER 3,008,596

ROLL CLAMP FOR LIFT TRUCK BY z/c/a'z M47742 EaGEerO MM/c/wvy ,cmeem/arou3,008,596 ROLL CLAMP FOR LIFT TRUCK Robert F. Oster, Fairview Park,Ohio, assignor to Towmotor Corporation, Cleveland, Ohio, a corporationof 7 Ohio Filed Jan. 27, 1958, Ser. No. 711,525

2 Claims. (Cl. 214-653) This invention relates to an industrial lifttruck and more particularly to a novel roll clamping apparatus for lifttrucks including clamping jaws and arms actuable by novel controlapparatus for handling heavy articles, such as rolls of paper. I

In the handling of large and heavy cylindrical articles such as rolls ofpaper by industrial lift trucks, it is advantageous for such a.truck tobe readily adaptable to handle objects of a rather wide range of sizessince in most cases such a wide range will be encountered, thuseliminating the need for separate trucks for handling the variousarticles. To accommodate articles of such a wide range of sizes,according to a novel feature of one embodiment of this invention one ofclamping jaws of a lift truck is adapted for compound linear and pivotalmovement relative to a linearly-movable clamping jaw whereby handling ofroll shaped articles of a wide range of sizes is enabled by a relativelyshort linear movement of either of the jaws. According to this feature,linear movement of the. clamping jaws is minimized and furthermore thetime'required in movement of thejaws from any one. position to any otherposition in their range is greatly decreased. According to anotherembodiment of the invention, gripping jaws that are movable strictly ina lineardirection maybe provided. In thiscase the structure of the jawsis somewhat simplified in that provisionfor pivotal movement of one ofthe jaws is not made. As another feature of the invention the compoundmovable jaw is of greater length than the linearly movable jaw wherebycylindrical or roll articles lying horizontally may be gripped, bypositioning the linearly movable jaw-beneath the roll and in engagementtherewith 3,008,596 Patented Nov; 14, 1961 of roll shaped articles suchas rolls of paper and to i provide an industrial truck apparatusadaptabl to pick up or set down suchan article in vertical orhorizontalposition.

It is another object of this invention to provide an industrial lifttruck with clamping or gripping jaws and control apparatus thereforefacilitating gripping and release of various roll shaped articles of awide range of sizes.

It is another object of this invention to provide an industrial lifttruck having a pair of opposed gripping or clamping jaws and controlapparatus facilitating an improved orderly.sequentialmovement of thejaws for gripping load articles.

It is another object of this invention to provide an in-, dustrial lifttruck having a pair of opposed clamping or gripping jaws one of which isadapted for compound movement for gripping a roll shaped article.

It is another object. of this invention to provide an industrial lifttruck having apair of opposed clamping or gripping jaws movable byrespective pairs of hydraulic piston cylinder arrangements and valvemeans actuated by movement of one of the arms to control the sequentialmovement of the other arm and the one arm for clamping or gripping aload article. I

It is another object of this invention to provide an industrial lifttruck having a pair of opposed clamping or gripping jaws at the ends ofrespective arms, one of which is pivotal about an end remote from thejaw as a fulcrum, by linear force applied at a point intermediate itslength.

at a point {near its contact with the floor, and by positioning thecompound movable jaw above the roll, and in contact therewith at a pointsubstantially diametrically opposite the point of contact of thelineatly movable In the one embodiment of this invention a pair ofopposed, cooperable, gripping or clamping jaws movable with respecttoeach other in either of two directions in a particular orderlysequence to effect gripping of a roll load, is provided. In retractivegripping movement from extended position, the sequential movement of thejaws for a small roll, comprises a linear movement of a first jaw towardthe second jaw, a linear movement of the second jaw toward the first jawand finally a pivotal movem'ent of the first jaw inthe motion of a thirdclass lever forcing 'the roll into engagement with the second jaw. Forlarger .loads the amount ofpivotal movement is progressively decreaseduntil no pivotal movement at all is "required by the first jaw to effectgripping. The pivotal movement of the first jaw in the motion of a thirdclass lever provides a wide range of movement of the gripping-portionthereof in response to relatively small linear movement of the firstjaw. Sincethe clamp of this invention is rotatable about a horizontalaxis, roll shaped articles may be gripped while standing on end orwhilelying ontheir sidefbetween the jaws of the present clamp andfmay beturned end for end or placedin any position inasmuch as the jawsfrictionally engage the roll and maintain the same in position.Accordingly, the roll may be set down in the same position in which itwas picked up or any other stable position. i

' It is an object of this invention to facilitate handling Other andfurther objects and advantages will. appear from a more detaileddescription of the invention'talten with the accompanying drawings inwhich:

FIG. 1 is a front elevational view of the entire clamping frameassembly;

FIG. 2 is a plan view of the invention;

FIG. 3 is an elevational view of the invention taken from the right sideof FIG. 1;

FIG. 4 is an elevation view of the invention taken from the left side ofFIG. 1;

FIG. 5 is a schematic representation of the hydraulic circuit foroperating the yarious components of the clamp frame assembly; I V I FIG.6 is a detail view showing schematically a portion of theinterior of avalve forming a part of the invention, and i FIG. 7 is a plan view 'of amodified embodiment of the invention. I

Referring now to FIG. l, 10frepresents the over-all clamp assembly whichmay be pivotally mounted on the forward end of a lift truck and whichmay also be raised and lowered by means not shown and forming no part ofthis invention.

Clamp assembly 10 comprises a quasi-stationary frame v 12, supported bya rotatable shaft 13 shown in FIG. 4,

and having a first pair of guid'eways 14 and 16 on which is slidable apair of complementary guideways 18 and 20 supporting a first jawassembly 22 of the clamp, and a second pair of guideways 24 and 26 onwhich is slidable a pair of complementary guideways 28 and 30 supportinga second jaw assembly 32.

Arm assemblies 22 and 32 are slidable along the respective guidewaysunder the influence of respectivepairs of piston-cylinder combinationscoupled between frame 12 and the appropriate arm assembly. A first pairof pistoncylinder combinations includes cylinders 34 and 36 each ends ofwhich are reduced to form shoulders abutting a portion of frame 12, andthe reduced portions are threaded and secured to the frame portion bynuts 44 and 46 engaging the respective threaded ends. Communications maybe established with the interior of respective ends of each cylinder 34and-36 through openings 48 and 50 on cylinder 34 and through openings 52and 54 on cylinder 36 for admitting or discharging hydraulic fluid toactuate the arm assembly 22. Hydraulic fluid circuit means hereinbelowset forth in detail is provided for controlling the fluid flowto andfrom these cylinders.

A second pair of piston-cylinder combinations for actuating jaw assembly32 includes a pair of cylinders 56 and 58 pivotally secured atrespective ends to frame 12 by sets of bolts 60 and 62 retainingapertured yokes 64 and 66 against frame 12 and in the apertures of whichyokes the respective ends of cylinders 56 and 58 have opposed pins. Eachcylinder 56 and 58 is provided with an internally slidable piston (notshown) connected to respective connecting rods 57' and 59 havingthreaded ends secured to jaw assembly 32 by nuts 65 and 67 engaging thesame and shown more clearly in FIG. 3 of the drawings. 'Jaw assembly 32may be'actuated by the influence of hydraulic fluid admitted intocylinders 56 and 58 through apertures 68 and 69 in cylinder 56 and 70and 71 in cylinder 58.

'As shown more clearly in FIG. 2 of the drawings, jaw assembly 22includes a curved clamping or gripping jaw 72 supported by a pair ofparallel arms 74 and 76 each secured at one end to the jaw 72 and at theother end to respective guideways 18 and 20. A planar member 78,apertured at 80 is secured to arms 74 and 76 for additional strength andfor providing an additional load gripping surface. A pair of brackets 82and 84 are secured between inner end portions of arms 74 and 76 and areprovided with apertures 86, 88, 90 and 92 for receiving pins 39 and 41extending therethrough and through lugs 38 and 40 shown in FIG. 1.

" Jaw assembly 32 includes a pair of arms 94 and 96 at the outer end ofwhich is secured a fiat member 98 having a hinge 100 for pivotallymounting a curved outer gripping shoe 102. A pair of springs 104 and 106secured at their respective ends to member 98 and shoe 102 urge theinner end of member 102 toward member 98.

t For automatically positioning an article to be lifted or carried inthe jaws of the truck, jaw assembly 32 includes a concave curved jawmember 103 extending arcuately from gripping member 102 to the guidewaysof the clamp where the surface of the jaw member 103 is nearly tangentto the straight guideways. Cooperative with jaw member 103 is acorresponding jaw member 105 movable with jaw assembly 22 which is alsocurved and substantially tangent with the guideways of the clamp.Accordingly, rolls which may be disposed vertically and. are gripped bythe clamp, are cammed forward by jaw members 103 and 105 to a morecentral location in the clamp. In the central position, shoe 102, whichpreferably. has a radius of curvature considerably greater than that ofjaw member 103 is engageable with the roll as hereinafter more fullyexplained.

A tubular shaft 108 is secured between one end of .arms 94 and 96 and ashaft 110 extending therethrough carries rollers 112 and 114 on the endsthereof, which rollers are preferably secured by appropriate snap ringsin annular grooves in the shaft.

Arms 94 and 96 are pivotal about a shaft 120 which extends between apair of plates 122 and 124 secured to guideways 28 and 30 and the shaftis secured in place by pins 126 and 128 extending through the shaft andthrough sockets 130 and 132 fixed to respective arms 122 and 124. Underthe force of hydraulic fluid in cylinders 56 and 58, jaw assembly 32 isretractable to the point where rollers 112 and 114 engage a pair of cams136 and 138 secured to the ends of guideways 14 and 16. Linear motion ofrollers 112 and 114 parallel to the guideways is accordingly restrictedwhile linear force continues to be imparted to shaft through plates 122and 124. Accordingly, rollers 112 and 114 are movable along earns 136and 138 normal to the direction of sliding motion along the guidewayswhereby arms 94 and 96 are pivotal and the outer clamping portions ofthe jaw assembly are pivotal also.

Disposed between arms 94 and 96 is a T-shaped web member 140 shown moreclearly in FIG. 1, which is provided with lug portions 142 and 144serving as bearings for eyebolts 146 and 148- threaded and secured inholes 150 and 152 in the lugs and adjustably secured thereto byrespective lock nuts 154 and 156. Each of a pair of coil springs 158 and160 is secured at one end to one of eyebolts 146 and 148 and at theother end to lugs secured to the outer portions of the jaw assembly.

A cam plate 162 is mounted by nut and bolt combinations 166 on a camsupport member 164 which in turn is secured to T-shaped web 140 bywelding or other suitable means. In addition, a cam plate 168 is securedto a cam support plate 170 by bolt and nut combinations 172. Plate 170is secured to frame 12 by welding or any other suitable means. drawingscams 162 and 168 are somewhat spaced so as to permit relative movementtherebetween.

As a component of the hydraulic system for effecting an orderlysequential movement of respective jaw assemblies 22 and 32, a valve 174described more fully hereinbelow is secured to the inner end of guideway18 and is provided with a valve plunger 1178 actuated by links and 181which are secured to the plunger and to a roller 182 engageable incertain positions, with cams 162 and 168. Either cam 162 or 168, whenpositioned below valve 174, is efieotive to lift plunger 178.

According to the present invention hydraulic fluid is admitted tocylinders 34, 36, 56 and 58 under the control ofa system shownschematically in FIG. 5 of the drawing to effect movement of jawassemblies 22 and 32.

' In the hydraulic system a hydraulic fluid pump (not shown) deliversfluid underpressure to a maincontrol valve 184 through a supply line 186and is distributed from valve 184 through either of two lines 188 or 190and is returned through either of the lines 188, 190 or a line 192 asthe occasion requires.

In the operation of the lift truck for clamping or gripping, valve 184is positioned to provide communication between line 186 and line 190whereby fluid is applied to valve 174. Assuming that the jaws of thelift truck are extended'and accordingly that roller 182 is out ofcontact with either cam 162 or 168, valve 174 directs fluid through aline 194 to a check valve 196 and there from, fluid flows through line198 to a T junction 200't0 charge an accumulator 202 and through a line203 to a terminal block 204 from where it flows equally in twodirections through lines 206 and 208 to respective rod ends of cylinders56 and 58. Fluid in opposite ends of these cylinders is exhausted atreturn line or low pressure, jointly through lines 210 and 212 toterminal block 214 and then through lines 216 and 188 back to the maincontrol valve 184. Accordingly, jaw assembly 32 is retracted to a pointwhere cam 162 reaches roller 182 and links 180, 181 and plunger 178 areactuated to operate the valve 174. In this new position of valve 174,fluid flow in line 194 is interrupted and fluid is applied through line218. Retraction of jaw assembly 32 is consequently interrupted andretraction of jaw assembly 22 is effected by reason of fluid flowthrough check valve 220, lines 222 and 224 to rod ends of cylinders 34and 36. Fluid is discharged from the opposite ends of cylinders 34 and36 through lines 226, 228, 230, 232 and 188 to the main conma valvewhereby jaw assembly 22 is retracted. Guide-' way 18, on which valve 174is mounted, moves with jaw assembly 22. Accordingly, 'roller 182advances along As shown in FIG. 2 of the cam plate 168 until it dropsoff the left side to allow plunger 178 of 'valve 174 to stop the fluidflow through line 218 and redirect it through line 194 wherebyretraction of jaw assembly 22 is terminated and retraction of jawassembly 32 is again effected.

The'initial retraction of jaw assembly 32 isefiective to move therollers 112 and 114 mounted on jaw assembly 32, approximately half wayfrom their outermost position toward'cam plate 136. During suchmovement, jaw member 103 is elfective with jaw member 105 to cam theroll article to a morecentral position within the clamp as hereinalboveexplained. The continued clamping move ment of jaw assembly 32 bringsthe rollers into contact with cam plates 136 whereby the continuedretractive force of cylinders 56 and 58 causes arms 94 and 96 to'beretracted and accordingly pivoted by shaft 120 toeffect a pivotalclamping motion to the jaw of assembly '32, Clamping action may becontinued as herein described, sufficiently to grasp a load forhandling, moving or positioning.

For releasing a load grasped by the clamping jaws of the invention,fluid under pressure -is directed from valve 184 to the internal fullarea of cylinders 56 and 58 through lines 188 and 216, terminal block214 and respective lines 210 and 212. Simultaneously therewith, fluidunder pressure is applied through-line 232 to operate the pilot releasemechanism of check .valve 196 to permit return flow of fluid fromaccumulator 202 and the rod ends of .cylinders 56 and 58 which exhaustthrough lines 206, 208, 203, 198, check valves 196, line 194 and valve174 to the sump. It is'noted that in these circumstances the plunger 178of valve 174 is positioned so as to block flow through line 218 wherebycylinders 34 and 36 remain inactive.

The immediately afioredescribed extension of jaw assembly 32 takes placeuntil cam 162 engages roller 182 causing an upward movement of plunger178 as seen in FIG. 1, which again interrupts communication betweenlines 190 and 194 and permits return flow from line 218 to pass throughline 192. Under these circumstances, fluid under pressure is appliedthrough lines 188, 232, 230, 228 and 226 to cylinders 34 and 36,extending the cylinders and jaw assembly 22 until roller 182 drops ofithe cam plate 168, actuating plunger 178, redirecting fluid throughvalve 174 whereby flow from the rod ends of cylinders 56 and 58 occursthrough valve 12. The jaws and assemblies are again fully extended androller 182 is in a position to enable jaw assembly 32 to retract firstrather than jaw assembly 22 which serves as a guide for the truckoperator in positioning the truck for picking up a load.

As schematically shown in FIG. 6 of the drawings, valve 174 comprises acasing in which a plunger 178 is reciprocable to unitarily reciprocate aplurality of pistons 240, 242 and 244 which control the flow ofhydraulic fluid from pressure line 190 to either of lines 194 and 218and from either of the lines 194 or 218 to return line 192 as the casemay be. As shown in FIG. 6, the position of the pistons direct fluidfrom pressure line 190 to line 194 and from line 218 to line 192. In anupper position as shown in dotted lines of the plunger, 190 wouldcommunicate with line 218 and line 194 with return line 192.

The versatility of the clamp of the present invention enables thehandling of roll articles larger than a predetermined minimum size whichinitially have axes horizontally disposed. Clamp assembly 10 is rotated90 with respect to its position in the drawing in a counterclockwisedirection looking forward from the rear thereof whereby jaw assembly 22is directly beneath jaw assembly 32 and is near the floor. The valvecontrols are manipulated by the operator to supply fluid to valve 174,whereby jaw assembly 32 is translated inwardly to the first automaticcut-ofl point and jaw assembly is translated inwardly to its cut-offpoint and then the valves are closed. Clamp assembly 10 is maneuvered soas to bring jaw 72 beneath the roll and jaw 103 and shoe 102 above theroll and gripping of the roll is effected by further pivotal motion ofjaw 103 to bring shoe 102 tightly against the roll. It is to be observedthat in positioning jaw 72 beneath the roll, the outer tip of this jawapproaches very nearly the lowermost point of the roll since the extremeouter portion of this jaw is straight to conform to 'a planar floorsurface on which the roll is placed; Also, when jaw 72 is brought intothis position, jaw'103 being considerably longer than jaw 72, extends toa point above the roll and beyond the uppermost point of the roll whereby pivotal motion of jaw 103 brings shoe 102 into contact with the rollat a point substantially diametrically oppositefthe point. of contact ofjaw 721 Accordingly, the roll cannot roll or slip away from the jaws.

In accordanceflwith a somewhat simplified embodiment of the invention.as shown in FIG. 7 of the drawingsa pair of jaw assemblies 22' and 32'similar in shape'and construction to jaw assemblies 22 and 32 of FIGURES1 through 5 are mounted for strictly linear movement relative to eachother and along guideways similar to guideways 18 and 20 of FIGURES l.through"5,; for gripping loads therebetween. In this embodiment ofinvention parts are constructed and arranged similar to those shown inFIGURES 1 through 6 with the exception that a jaw 103' similar to jaw103 is rigidly rather than pivotally mounted and is further free to movelinearly toward or away from the other 'jaw within the limits as shownin full and in phantom lines since no limiting cam plate similar to camplate 136 shown in FIGURES 1 through 5 is provided. Analogous parts areindicated by the same numbers primed.

It is to be understood that the automatic and sequential movement of thejaw assemblies 22' and 32' of this embodiment of invention for grippingand releasing loads is effected in a manner entirely similar tothatdisclosed with respect to FIGURES 1 through 6 with the exceptionthat no pivotal movement of either jaw is provided for. The jaws arelinearly movable alternatively in three steps as hereinabove describedfor small loads and in progressively fewer steps as the size of the loadhandled increases.

In FIG. 7 an arm 250 is mounted for linear movement along the guidewaysof the truck carriage under the influence of a hydraulically actuatedpiston 57' and supports a curved shoe 102 at its outer end forengagement with a load article. Shoe 102' is mounted on a pivot and isbiased by a spring 104'. An inner portion of arm 250 has secured theretoa curved jaw member 252 for camming gripped articles into position forengagement by shoe 102'.

Having thus described this invention in such full, clear, concise andexact terms as to enable any person skilled in the art to which itpertains to make and use the same} and having set forth the best modecontemplated of carrying out this invention, I state that the subjectmatter which I regard as being my invention is particularly pointed outand distinctly claimed in what is claimed, it being understood thatequivalents or modifications of, or substitutions for, parts of theabove specifically described embodiment of the invention may be madewithout departing from the scope of the invention as set forth in whatis claimed.

I claim:

1. Hydraulic apparatus for the sequential operation of roll clamp jawsfor a lift truck clamp comprising a frame, a first clamping jaw slidableon the frame, a second clamping jaw slidable on the frame, firsthydraulic cylinder means for moving the first clamping jaw, secondhydraulic cylinder means for moving said second clamping jaw, a manuallyoperable valve, a source of hydraulic fluid pressure connected to saidmanually operable valve, a sequence valve mounted on said secondclamping jaw and movable therewith relative to said frame, a sequencevalve cam mounted on said first clamping jaw and movable therewithacross the frame in a path adjacent to the path of movement of saidsequence valve, conduit means to conduct hydraulic fluid under pressurefrom said manually operable valve to 7 said sequence valve, and conduitmeans connecting said sequence valve and said first hydraulic cylindermeans to move said first clamping jaw across said frame and toward saidsecond clamping jaw, a movable actuator mounted on said sequence valve,said movement of said first clamping jaw effective to bring saidsequence valve cam into engagement with said movable actuator on thesequence valve, conduit means connecting said sequence valve'and saidsecond hydraulic cylinder means to direct hydraulic fluid under pressureto said second hydraulic cylinder ,means and move said second clampingjaw across the frame toward said first clamping jaw, said movement ofsaid second clamping j-aw being efiective to move said sequence valvecarried thereby relative to the sequence valve cam carried by said firstclamping jaw and thus disengage said actuator with respect to said earnplate.

2. Hydraulic apparatus for the sequential operation of roll clamp jawsfor a lift truck clamp comprising a frame, a first clamping jaw arrangedto'be extended and retracted on the frame, a second clamping jawarranged to be extended and retracted on the frame, first hydrauliccylinder means for moving the first clamping jaw, second hydrauliccylinder means for moving said second clamping jaw, a manually operablevalve, a source of hydraulic fluid pressure connected to said manuallyoperable valve, a sequence valve mounted on said second clamping jaw andmovable therewith in a reciproeating path near the mid-portion of saidframe, a sequence valve cam mounted on said first clamping jaw andmovable therewith across the frame in a reciprocating path adjacenttothe p'athlof' movement of said sequence valve, conduit means toconduct hydraulic fluid under pressure from said manually operable valveto said sequence valve, and conduit means connecting said sequence valveand said first hydraulic cylinder means to move said first clamping jawacross said frame and toward said second clamping jaw, a movableactuator mounted on said sequence valve, said movement of said firstclamping jaw effective to bring said sequence cam into engagement withsaid movable actuator on the sequence valve, conduit means connectingsaid sequence valve and said second hydraulic cylinder means to directhydraulic fluid under pressure to said second hydraulic cylinder meansand move said second clamping jaw across the frame toward said firstclamping jaw, said movement of said second clamping jaw being elfectiveto move said sequence valve relative to the cam plate carried by saidfirst clamping jaw.

References Cited in the file of this patent UNITED STATES PATENTS2,596,477 Freischmann et al. May 13, 1952 2,667,282 MacDonald et al Jan.26, 1954 2,752,055' Hoppert June 26, 1956 2,757,813 Adams Aug. 7, 19562,815,878 Vance Dec. 10, 1957 2,874,862 Farmer et al. Feb. 24, 1959

